1. Field of the Invention
The invention is generally related to electronic component manufacturing, including printed circuit board (PCB) and integrated circuit (IC) manufacturing. More particularly, this invention is related to an in-line monitor for non-destructively evaluating the state of cure and percent imidization of thick (&gt;1 .mu.m) meta-paete (pyromellitic dianhydride-oxydianiline ethyl ester) polyimide films.
2. Description of the Prior Art
Ginsburg et al., IBM Technical Disclosure Bulletin Vol. 25, No. 8, January 1983, discloses that Fourier transform infrared (FTIR) spectroscopy techniques have been used in the past to monitor the degree of imidization of polyimide work pieces. The detected degree of imidization can be used to adjust on-line fabrication parameters.
U.S. Pat. No. 3,524,983 to Voeltz discloses a process and apparatus for determining the cure characteristics of materials which utilizes infrared radiation that is passed through a sample and reflected back through the sample by a reflective surface which supports the sample. A sensor monitors changes in the intensity of the reflected beam and the cure characteristics are determined by absorption changes.